Ion Milling Device and Ion Milling Method

ABSTRACT

Provided is a machining technology to obtain a desired machining content while suppressing a possibility of causing a redeposition in a machining surface. The invention is directed to provide an ion milling device which includes an ion source which emits an ion beam, a sample holder which holds a sample, and a sample sliding mechanism which slides the sample holder in a direction including a normal direction of an axis of the ion beam.

TECHNICAL FIELD

The present invention relates to an ion milling device and an ionmilling method, for example, an ion milling device and an ion millingmethod to prepare a sample which is observed by a scanning electronmicroscope (SEM) or a transmission electron microscope (TEM).

BACKGROUND ART

An ion milling device is a device which emits an argon ion beam to asurface or a cross section of metal, glass, or ceramics to polish, andis suitable as a pre-treatment device for observing the surface or thecross section of a sample using the electron microscope.

In the related art, when observing the cross section of the sample usingthe electron microscope, an area around an observing portion is cutusing a diamond cutter or a fret saw, and then the cross section ismechanically polished, and attached to a sample stand for the electronmicroscope to observe an image. In the case of observing a polymericmaterial or a soft sample such as aluminum, when mechanically polishing,the observing surface is crushed or a deep damage is left due toparticles of a polishing material. In addition, for example, in the caseof observing a rigid sample such as glass or ceramics, it is hard toperform the polishing. In the case of observing a composite formed bystacking soft materials and rigid materials, it is extremely hard tomachine the cross section.

With this regard, using an ion milling the soft sample can be machinedwithout crushing the surface shape, and the rigid sample and thecomposite material can be polished. In addition, the cross section in amirror state can be effectively obtained. For example, PTL 1 disclosesan ion milling device which emits the ion beam while inclining orrotating the sample to suppress irregularities in a streak shape in amachining surface.

CITATION LIST Patent Literature

PTL 1: JP-A-2014-139938

SUMMARY OF INVENTION Technical Problem

The inventor of the present application has extensively studied amachining method in a cross-sectional milling, and as a result found outthe following knowledge.

The cross-sectional milling means a process in which a part of the ionbeam is shielded by a mask (shielding plate) disposed on the upperportion of a sample, and the cross section of the sample along the endsurface of the mask is subjected to sputtering. As a result, the crosssection of the sample along the end surface of the mask is obtained.

However, in a case where there is a need to perform the machining withrespect to a machining width (observation width) equal to or greaterthan an ion beam width or a plurality of machining points, a samplechamber is opened to the air, a machining position is changed, and thesample chamber is evacuated again, and then an additional machining isnecessarily performed. When such an additional machining is performed, athroughput is lowered.

The invention has been made in view of the problems, and an objectthereof is to provide a machining technology of obtaining a desiredmachining content while preventing a throughput reduction.

Solution to Problem

In order to solve the above problems, there is provided an ion millingdevice which machines a sample by emitting an ion beam to the sample ofwhich at least a part is shielded by a mask. The ion milling deviceincludes an ion source which emits the ion beam, a sample holder whichholds the sample, and a sample sliding mechanism which slides the sampleholder in a direction including a normal direction of an axis of the ionbeam.

Advantageous Effects of Invention

According to the above configuration, it is possible to improve athroughput.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a diagram illustrating a first configuration example of an ionmilling device according to the embodiment.

FIG. 2 is a diagram illustrating a configuration example of a main bodyof a sample mask unit 21.

FIG. 3 is a diagram illustrating another configuration example of thesample mask unit 21.

FIG. 4 is a diagram for describing a method of arranging a cross sectionof a sample and a mask in parallel.

FIG. 5 is a diagram illustrating a configuration of a sample stagedrawing mechanism 60.

FIG. 6 is a diagram illustrating a configuration example of an opticalmicroscope 40 which is used to observe a shielding positional relationbetween a mask 2 and a sample 3.

FIG. 7 is a diagram illustrating a state where a sample mask unitmicromotion mechanism 4 provided with the sample mask unit 21 is fixedon a fixing base 42.

FIG. 8 is a diagram for describing a method of matching the center of anion beam with a portion of the sample 3 where a cross section polishingis desired to be performed.

FIG. 9 is a diagram for describing a method of mirror-polishing a crosssection of the sample 3 using the ion beam.

FIG. 10 is a diagram illustrating a second configuration example of theion milling device according to an embodiment which is different fromthe configuration of the first configuration example, capable ofperforming a cross-sectional milling and a planar milling.

FIG. 11 is a diagram illustrating a configuration example of the samplemask unit micromotion mechanism 4 in which the sample mask unit 21mounted in the ion milling device illustrated in FIG. 10 is installed.

FIG. 12 is a diagram for describing a rotation mechanism which isprovided in a sample unit base 5 and rotates a mask unit fixing unit 52.

FIG. 13 is a diagram illustrating the rotation mechanism which rotatesthe mask unit fixing unit 52 by rotating a shaft coupling 53.

FIG. 14 is a diagram illustrating a state where the sample mask unitmicromotion mechanism 4 is installed in the optical microscope 40 toadjust a machining position.

FIG. 15 is a diagram illustrating a configuration example of a rotationslope mechanism, and more particularly a diagram illustrating aconfiguration of portion A surrounded by a dotted line of FIG. 12.

FIG. 16 is a diagram illustrating a mechanism to rotate a rotatingmember 9 by the shaft coupling.

FIG. 17 is a diagram illustrating a configuration example of a slidemilling holder (slide movement mechanism) 70 which slides the samplemask unit micromotion mechanism 4 in an X-axis direction.

FIG. 18 is a diagram illustrating a connection relation between deviceswhen a machining position of the ion milling is set.

FIG. 19 is a flowchart for describing a procedure of a machiningposition setting process.

FIG. 20 is a diagram illustrating a layout example of buttons forsetting a target position in a control BOX 80.

FIG. 21 is a diagram illustrating a first specific example of amachining region setting method of a wide region milling.

FIG. 22 is a diagram illustrating a second specific example of themachining region setting method of the wide region milling.

FIG. 23 is a diagram illustrating an exemplary operation screen forsetting a machining region in the wide region milling.

FIG. 24 is a diagram for describing a machining procedure of the sample3 by the wide region milling.

FIG. 25 is a diagram illustrating a range of a slide operation and areciprocating slope operation in a case where the slide movementmechanism (the slide milling holder 70) is installed below the rotatingmember 9.

FIG. 26 is a diagram illustrating a state when the sample mask unit 21rotates and slides in a case where the slide movement mechanism (theslide milling holder 70) is installed below the rotating member 9.

FIG. 27 is a diagram illustrating a range of the slide operation and thereciprocating slope operation in a case where the slide movementmechanism (the slide milling holder 70) is installed on the rotatingmember 9.

FIG. 28 is a diagram illustrating a specific example of the machiningregion setting method of a multipoint milling.

FIG. 29 is a diagram for describing a first machining procedure of thesample 3 by the multipoint milling.

FIG. 30 is a diagram for describing a second machining procedure tosuppress a redeposition caused by the multipoint milling.

FIG. 31 is a diagram illustrating an application of the wide regionmilling.

FIG. 32 is a diagram for describing a method of fixing a plurality ofsamples having different thicknesses.

FIG. 33 is a diagram illustrating a state where a plurality of sampleshaving different thicknesses are arranged and fixed to a mask.

FIG. 34 is a diagram illustrating a state where a sample havingdifferent thickness is machined and moved to an observation device forobservation.

FIG. 35 is a diagram illustrating a connection relation between deviceswhen the machining position of the ion milling is set according to amodification.

FIG. 36 is a flowchart for describing a procedure of a machiningposition setting process according to the modification.

DESCRIPTION OF EMBODIMENTS

In general, in a case where a machining is required to be performed withrespect to a width (observation width) which is larger than an ion beamwidth and a plurality of machining points, a sample chamber is opened tothe air, a machining position is changed, the sample chamber isevacuated and exhausted, and then an additional machining is performed.When such an additional machining is performed, a throughput is lowered.In addition, a redeposition is highly likely to occur in a machiningsurface at the first time.

Therefore, according to an embodiment of the invention, followings arerealized. That is, a redeposition caused by the ion milling is extremelysuppressed while improving the throughput, a desired width (a widthwider than the ion beam width) of machining surface is generated on thesample, and/or a plurality of machining points (machining places) aregenerated on the sample. The present specification discloses at least amechanism and a processing procedure in which a desired width ofmachining surface is generated and a plurality of machining points aregenerated by one time of machining process.

Hereinafter, embodiments of the invention will be described withreference to the drawings. In the embodiment, the description will begiven about an ion milling device in which an ion source is mounted toemit an argon ion beam, but the ion beam is not limited to the argon ionbeam, and various ion beams may be employed.

<Configuration Example of Ion Milling Device>

(i) First Configuration Example of Device

FIG. 1 is a diagram illustrating a first configuration example of an ionmilling device 100 according to the embodiment. The ion milling device100 of FIG. 1 includes a vacuum chamber 15, an ion source 1 which isattached to the upper surface of the vacuum chamber, a sample stage 8which is provided on the front surface of the vacuum chamber 15, asample unit base 5 which extends from the sample stage 8, a sample maskunit micromotion mechanism 4 which is placed on the sample unit base 5,a sample mask unit 21 which is placed on the sample mask unitmicromotion mechanism 4, an evacuation system 6, and a linear guide 11which is provided on the front surface of the vacuum chamber 15. Asample 3 and a mask 2 are placed on the sample mask unit.

The sample mask unit micromotion mechanism 4 is mounted in the sampleunit base 5. When mounting, the lower surface of the sample mask unitmicromotion mechanism 4 (a surface opposite to the mask surface wherethe ion beam is emitted) and the upper surface of the sample unit base 5come into contact with each other, and fixed with a screw. The sampleunit base 5 is configured to rotate and tilt at an arbitrary angle withrespect to an optical axis of the ion beam. A tilting direction and atilting angle of the rotation are controlled by the sample stage 8. Thesample 3 disposed on the sample mask unit micromotion mechanism 4 can beset to form a predetermined angle with the optical axis of the ion beamby rotating and tilting the sample stage 8. Further, a rotation tiltingshaft of the sample stage 8 and the upper surface of the sample (thelower surface of the mask) are matched in position, and a smoothmachining surface is manufactured with efficiency. In addition, thesample mask unit micromotion mechanism 4 is configured to move front,back, right, and left in the vertical direction with respect to theoptical axis of the ion beam (that is, an X direction and a Ydirection).

The sample unit base 5 is disposed through the sample stage 8 (rotationmechanism) which is mounted on a flange 10 also serving as a part of thewall of the vacuum chamber 15. When the flange 10 is drawn out along thelinear guide 11 to open the vacuum chamber 15 to the air, the sampleunit base 5 is drawn out to the outer side of the vacuum chamber 15. Inthis way, a sample stage drawing mechanism is configured.

FIG. 2 is a diagram illustrating a configuration example of a main bodyof the sample mask unit 21. FIG. 2 (a) is a top view, and FIG. 2(b) is aside view. In the embodiment, an integrated configuration of at least asample holder 23 and the rotation mechanism thereof, and the mask 2 anda fine adjustment mechanism thereof is called the sample mask unit (mainbody) 21. In FIG. 2, a sample holder rotation ring 22 and a sampleholder rotation screw 28 are provided as the rotation mechanism of thesample holder 23. The sample holder 23 perpendicular to the optical axisof the ion beam can be rotated by rotating the sample holder rotationscrew 28. In addition, the sample holder rotation ring 22 is configuredto rotate by turning the sample holder rotation screw 28, and returns bya spring force of a reverse rotating spring 29.

The sample mask unit 21 includes a mechanism with which a position and arotation angle of the mask can be finely adjusted, and is configured tobe attached and detached with respect to the sample mask unitmicromotion mechanism 4. In the embodiment, the sample mask unit 21 andthe sample mask unit micromotion mechanism 4 are divided into twocomponents, but may be configured in one component (in the embodiment,the description of the sample mask unit and the sample mask unitmicromotion mechanism will be separately given in order to help withunderstanding).

The mask 2 is fixed to a mask holder 25 by a mask fixing screw 27. Themask holder 25 moves along a linear guide 24 by operating a mask fineadjustment mechanism (that is, a mask position adjusting unit) 26, andthus the positions of the sample 3 and the mask 2 are finely adjusted.The sample holder 23 is inserted to the sample holder rotation ring 22from the lower side and fixed. The sample 3 is bonded and fixed to thesample holder 23 (for example, carbon paste, white wax, double-sidedtape, etc.). A position of the sample holder 23 in the height directionis adjusted by a sample holder position control mechanism 30, and thesample holder 23 is tightly fixed to the mask 2.

FIG. 3 is a diagram illustrating another configuration example of thesample mask unit 21. In this configuration example, a sample holdermetal fitting 35 is used to suppress the sample holder 23, and the otherconfigurations are basically the same as those of the configurationexample illustrated in FIG. 2. FIG. 3(a) illustrates a state where thesample holder 23 fixed with the sample 3 is mounted in the sample maskunit 21. FIG. 3(b) illustrates a state where the sample holder 23 fixedwith the sample 3 is taken out of the sample mask unit 21.

FIG. 4 is a diagram for describing a method of arranging the crosssection of the sample and the mask in parallel. The sample holderrotation screw 28 is turned to adjust the position in an X1 direction,and a fine adjustment is performed under the microscope such that thecross section of the sample 3 and a ridge line of the mask 2 are alignedin parallel as described below. At this time, the mask fine adjustmentmechanism 26 is turned to make the cross section of the sample 3slightly protrude from the mask (for example, to protrude about 50 μm).

FIG. 5 is a diagram illustrating a configuration of a sample stagedrawing mechanism 60. The sample stage drawing mechanism 60 isconfigured of the linear guide 11 and the flange 10 which is fixed tothe linear guide. The sample unit base 5 which is fixed to the samplestage mounted on the flange 10 is drawn out of the vacuum chamber 15along the linear guide 11. With this operation, the sample mask unitmicromotion mechanism 4 on which the sample mask unit 21 installed thatis, the mask 2, the sample holder 23, and the sample 3 are integrallydrawn out of the vacuum chamber 15 on the sample unit base 5.

In the embodiment, the sample mask unit micromotion mechanism 4 on whichthe sample mask unit 21 installed is configured to be detachably fixedto the sample unit base 5. Therefore, when the sample mask unitmicromotion mechanism 4 on which the sample mask unit 21 installed isdrawn out to the outer side of the vacuum chamber 15, the sample maskunit micromotion mechanism 4 on which the sample mask unit 21 installedis detachable from the sample unit base 5 (detachable standby of thesample mask unit 21).

FIG. 5 is a diagram illustrating a state where the sample mask unitmicromotion mechanism 4 on which the sample mask unit 21 installed isdetached in the detachable state. The detaching may be performedmanually, or may be performed using an appropriate tool.

FIG. 6 is a diagram illustrating a configuration example of an opticalmicroscope 40 with which a shielding positional relation between themask 2 and the sample 3 is observed. As illustrated in FIG. 6, thesample mask unit micromotion mechanism is configured separately from thevacuum chamber 15, and may be disposed at an arbitrary place. Then, theoptical microscope 40 includes a well-known loupe 12 and a loupemicromotion mechanism 13. Further, the optical microscope 40 includes afixing base 42 to install the taken-out sample mask unit micromotionmechanism 4 on which the sample mask unit 21 installed onto anobservation stand 41. Then, the sample mask unit micromotion mechanism 4on which the sample mask unit 21 installed is installed on the fixingbase 42 at reproducible positions which are set by positioning shaftsand holes.

FIG. 7 is a diagram illustrating a state where the sample mask unitmicromotion mechanism 4 on which the sample mask unit 21 installed isfixed onto the fixing base 42. In this way, since the sample mask unitmicromotion mechanism 4 on which the sample mask unit 21 installed isfixed onto the fixing base 42, a portion of the sample where a crosssection polishing is to be performed is matched with the center (“+” inFIG. 8) of the ion beam by a method to be described using FIG. 8.

FIG. 8 is a diagram for describing a method of matching a portion of thesample 3 where a cross section polishing is to be polished with thecenter of the ion beam. Photosensitive paper or copper foil is attachedto the sample holder 23, and a mark (that is, the center of the ionbeam) generated by the emitting of the ion beam and the center of theloupe are matched with each other by driving X2 and Y2 using the loupemicromotion mechanism 13. Therefore, the center of the ion beam and thecenter of the optical microscope correspond to each other in aone-to-one manner. Further, the position adjustment is performed attiming of a cleaning process. Then, the photosensitive paper or thecopper foil used in matching positions is taken out of the sample holder23, and the sample mask unit micromotion mechanism 4 on which the samplemask unit 21 installed is installed in the fixing base 42 after thesample 3 is mounted. The position of the sample mask unit micromotionmechanism 4 is adjusted in X3 and Y3 directions to match the portionwhere the cross section polishing is performed with the center of theloupe. Therefore, it is possible to match the center of the ion beamwith the portion where the cross section polishing is performed. In thisway, at the time of adjusting the shielding positional relation betweenthe mask 2 and the sample 3, the sample mask unit micromotion mechanism4 on which the sample mask unit 21 installed is taken out of the sampleunit base 5 and mounted to the fixing base 42 of the optical microscope40. The shielding positional relation of the mask 2 with respect to thesample 3 is adjusted by the mask position adjusting unit (mask fineadjustment mechanism).

FIG. 9 is a diagram for describing a method of mirror-polishing thecross section of the sample 3 using the ion beam. When the argon ionbeam is emitted, the sample 3 not covered with the mask 2 can be removedin a depth direction along the mask 2, and the surface of the crosssection of the sample 3 can be mirror-polished.

In this way, the sample mask unit micromotion mechanism 4 on which thesample mask unit 21 installed including the mask 2 of which theshielding positional relation with respect to the sample is adjusted atthe time of ion milling, is returned to the sample unit base 5, andmounted thereto.

As described above, the ion milling method is configured such that, atthe time of adjusting the shielding positional relation between the mask2 and the sample 3, the sample mask unit micromotion mechanism 4 onwhich the sample mask unit 21 installed is taken out of the sample unitbase 5 and mounted to the fixing base 42 of the optical microscope 40,and the shielding positional relation with respect to the sample 3 ofthe mask is adjusted. Further, the sample mask unit micromotionmechanism 4 on which the sample mask unit 21 installed including themask 2 of which the shielding positional relation with respect to thesample is adjusted, is returned into the vacuum chamber 15 at the timeof ion milling, and mounted to the sample unit base 5.

(ii) Second Configuration Example of Device

FIG. 10 is a diagram illustrating a second configuration example of theion milling device 100 according to the embodiment which is differentfrom the configuration of the first configuration example, and capableof performing a cross-sectional milling and a planar milling.

The ion milling device 100 includes the vacuum chamber 15, a machiningobservation window 7 which is provided in the upper surface of thevacuum chamber 15, the ion source 1 which is provided in the left sidesurface (or may be in the right side surface) of the vacuum chamber 15,the flange 10 which is provided in the side surface different from theside surface where the ion source 1 is provided, the sample stage 8which is provided on the flange 10, the sample unit base 5 which extendsfrom the sample stage 8, the sample mask unit micromotion mechanism 4and the sample mask unit 21 which are mounted on the sample unit base 5,the sample stage 8 which is provided on the front surface of the vacuumchamber 15, a shutter 101 which is provided between the sample and themachining observation window 7, and the evacuation system 6. The samplemask unit 21 includes the mask 2, and the sample 3 is placed therein.

The shutter 101 is installed to prevent sputtered particles fromdepositing on the machining observation window 7. The vacuum chamber 15is formed in a box shape or a similar shape which forms a space to makea normal vacuum atmosphere. The machining observation window 7 isprovided in the upper side of the box (a direction opposite to adirection of the gravitational field under a gravitational environment).The ion source 1 is provided in a side wall surface of the box (thesurface adjacent to the upper surface of the box in a directionperpendicular to the gravitational direction). In other words, themachining observation window 7 is provided in the wall surface of thevacuum chamber. Further, the optical microscope (including theobservation window) or an electron microscope may be installed in theopening for the machining observation window in addition to the windowwhich can vacuum-seal.

FIG. 11(a) is a diagram illustrating a configuration example of thesample mask unit micromotion mechanism 4 on which the sample mask unit21 installed which is mounted in the ion milling device illustrated inFIG. 10. The basis configurations are the same as those illustrated inFIGS. 2 and 3 except that a mask unit fixing unit 52 is provided in thesample mask unit micromotion mechanism 4 on which the sample mask unit21 is mounted. In addition, a fixing method of the sample holder 23 isdifferent from the configuration of FIG. 2. In other words, a keyportion 231 of the sample holder 23 is inserted to the sample holderrotation ring 22 (a shape obtained by dividing the ring in half) fromthe lower side, and fixed with a screw (see FIG. 11(b)). With such afixing method, the machining surface of the sample 3 can be observedfrom the machining observation window 7.

FIG. 12 is a diagram for describing the rotation mechanism which isprovided in the sample unit base 5 to rotate the mask unit fixing unit52. In the sample unit base 5, there is provided a rotating member 9 inwhich a sample holding member (a member to hold the sample including thesample mask unit micromotion mechanism 4) can be placed. The rotatingmember 9 serves as a support base to support the sample holding member.The sample unit base 5 is constituted by the rotating member 9, a gear50, and a bearing 51. The sample mask unit micromotion mechanism 4 isbrought into contact with a fixing surface (rear surface) of the samplemask unit micromotion mechanism 4 and the upper surface of the rotatingmember 9 of the sample unit base 5, and mounted by being fixed with ascrew from the mask unit fixing unit 52. The sample unit base 5 does notrotate and tilt, but is configured to rotate and tilt by the rotatingmember 9 mounted in the sample unit base 5 to form an arbitrary anglewith the optical axis of the ion beam which is emitted in the sidesurface direction of the vacuum chamber 15. A tilting direction and atilting angle of the rotation is controlled by the sample stage 8.

Herein, as a method of rotating and tilting the rotating member 9 of thesample unit base 5, there are a method of rotating the sample stage 8 asillustrated in FIG. 12 and a method of rotating a shaft coupling 53 asillustrated in FIG. 13, and both methods may be employed. The sample 3disposed on the sample mask unit micromotion mechanism 4 can be set at apredetermined angle with respect to the optical axis of the ion beam byrotating and tilting the rotating member 9 of the sample unit base 5.Further, a rotation axis of the rotating member 9 of the sample unitbase 5 and a position of the upper surface (the lower surface of themask) of the sample are matched to each other to prepare a smoothmachining surface with efficiency.

FIG. 14 is a diagram illustrating a state where the sample mask unitmicromotion mechanism 4 is installed on the optical microscope 40 toadjust the machining position. Further, the installation of the deviceand other units to the optical microscope 40 may be performed not usingthe mask unit fixing unit 52 but using the lower surface of the samplemask unit micromotion mechanism 4. FIG. 14 is different from FIG. 6 inthat the loupe micromotion mechanism 13 adjusting the center of the beamand the center of the loupe is installed on the fixing base 42. Theloupe micromotion mechanism 13 may be configured by employing any one ofthis example and the example of FIG. 6. Other operations are the same asthose of the example of FIG. 6.

FIG. 15 is a diagram illustrating a configuration example of a rotationslope mechanism, and more specifically a diagram illustrating aconfiguration of portion A surrounded by a dotted line of FIG. 12. Theion milling device according to the second configuration example (FIG.10) has a function of rotating a sample toward the rotation slopemechanism as illustrated in FIG. 15, and there is provided a tiltingmechanism which has a rotation tilting shaft in the vertical directionto an ion beam axis. The rotation slope mechanism is configured torotate the rotating member 9 (not illustrated in FIG. 15) using arotation force of a motor 55 through a shaft and the gear 50. With thisconfiguration, it is possible to realize an eccentric mechanism whichdisplaces the ion beam axis and rotation axis of the sample mask unitmicromotion mechanism 4 when the tilting angle is 90 degrees. Further,as illustrated in FIG. 16, the shaft coupling may be used. However, in acase where the shaft coupling is used, the shaft coupling is installedin a rotation tilting unit as illustrated in FIG. 16, and the eccentricmechanism (moves in the Y-axis direction) is desirably installed in thelower portion of the rotating member 9 of the sample unit base 5.

As illustrated in FIGS. 15 and 16, the ion milling device may have afunction of rotating the sample. The incident angle of ion beam and aneccentric amount are arbitrarily set such that the planar milling(smoothening a surface (when the tilting angle of the sample stage is 90degrees) perpendicular to the ion beam axis) may be performed whileperforming the cross-sectional milling (milling the sample through amask to make the surface smooth).

<Slide Movement Mechanism to Realize Wide Region Milling and MultipointMilling>

Hereinafter, the description will be given about a slide movementmechanism to realize a wide region milling and a multipoint milling inthe ion milling device 100 according to the configuration of FIGS. 1 and10 (including any one of FIGS. 12, 13, 15, and 16). Herein, the wideregion milling means a machining which is performed on a region on thesample having a width wider than the ion beam width. In addition, themultipoint milling means a machining which is performed on a pluralityof places on the sample (in particular, an automatic machining performedon a plurality of places in this embodiment).

The ion milling device 100, which is possible to execute the wide regionmilling and the multipoint milling, includes the slide movementmechanism (also referred to as a slide driving mechanism) which ismovable (slidable) in a vertical direction with respect to the opticalaxis of the ion beam, and necessarily slides the sample mask unit 21 inthe vacuum chamber. A direction of sliding movement and the edge of themask 2 are desirably arranged in parallel. Further, the position of therotation tilting shaft desirably does not move even when the slidingmovement is performed (the reason will be described below with referenceto FIGS. 25 to 27). Such an ion milling device may be realized by thefollowing configuration. Further, the description in the embodiment willbe given about a case where a motor (a drive source in an X-axisdirection) is installed in the vacuum chamber (at the time of drivingthe motor). However, the motor may be installed outside the chamber.

In order to perform the wide region milling and the multipoint milling,the sample mask unit micromotion mechanism 4 is desirably driven in theX-axis direction (see FIG. 10) in the vacuum chamber 15 in addition tothe configuration of FIG. 10. Specifically, it is possible to drive thesample mask unit micromotion mechanism 4 in the X direction in thevacuum chamber 15 by using a motor as the drive source of the Xdirection.

FIG. 17 is a diagram illustrating a configuration example of a slidemilling holder (slide movement mechanism) 70 to slide the sample maskunit micromotion mechanism 4 in the X-axis direction. In the slidemilling holder 70, there is provided an X gear 71 in a drive axis of thesample mask unit micromotion mechanism 4 in the X-axis direction. Inaddition, a motor unit 72 is installed on the lower surface side of thesample mask unit micromotion mechanism 4. The motor unit 72 isconstituted by a motor, an M gear 73, and a cover. M gear 73 isassembled into the rotation axis of the motor (the M gear 73 may not bedirectly attached to the rotation axis of the motor). The M gear is afinal stage gear which is through a plurality of gear stages and comesinto contact with the X gear 71. The sample mask unit micromotionmechanism 4 and the motor unit 72 may be configured integrally orseparately. The description herein will be given about the separatetype. In the separate type, a normal cross-sectional milling is possible(manually adjusting method) even after the motor unit 72 is taken out.

The sample mask unit micromotion mechanism 4 and the motor unit 72 areassembled by a shaft and a hole for positioning while keeping areproducible positional relation, and fixed by a screw. With thisconfiguration, the X gear 71 of the sample mask unit micromotionmechanism 4 and the M gear 73 of the motor unit 72 come into contactwith each other. Therefore, when the motor starts to rotate, the X gear71 rotates through the M gear 73, and a drive shaft of the sample maskunit micromotion mechanism 4 in the X-axis direction rotates. Therefore,the sample 3 (the sample 3 fixed to the sample mask unit 21) starts tomove (slide) in the X-axis direction. With this configuration, it ispossible to realize the ion milling device in which the rotation tiltingshaft does not move while performing sliding. Further, the slide millingholder 70 is disposed on the upper portion of the rotating member 9 inthe ion milling device as illustrated in FIGS. 10 and 12. In addition,the slide milling holder 70 is placed on the sample unit base 5 in theion milling device illustrated in FIG. 1.

<Processing Content from Machining Target Position Setting to MachiningStart>

FIG. 18 is a diagram illustrating a connection relation between deviceswhen a machining position of the ion milling device is set. FIG. 19 isflowchart for describing a procedure of a machining position settingprocess. The description will be given with reference to FIGS. 18 and 19about a method of operating of the ion milling using the slide millingholder 70 where the sample mask unit micromotion mechanism 4 on whichthe sample mask unit 21 installed and the motor unit 72 are assembled(an operation in a state where the sample 3 is disposed on the samplemask unit 21). Further, power for driving the motor is supplied from acontrol unit 103 of the main body of the ion milling device 100 througha motor cable (out) 74 and the motor cable (in) 75.

(i) Step 1901

A user (operator) mounts the slide milling holder 70 to the fixing base42 of the optical microscope 40 (see FIG. 14), and connects the motorcable (out) 74 extending from the control unit 103 through an opticalmicroscope driver 102 to the motor unit of the slide milling holder 70.

(ii) Step 1902

When the machining position setting process starts after Step 1901, thecontrol unit 103 performs an initialization operation of the slidemilling holder 70. Specifically, the slide milling holder 70 mounted inthe optical microscope 40 is moved to a reference position (for example,an origin point).

(iii) Step 1903

After completing the initialization operation, the user presses an arrowbutton provided on an operation unit (for example, a touch panel) 81 oron a control BOX (for example, installed away from the control unit 103,and close to the optical microscope 40) 80, moves the slide millingholder 70 provided with the sample 3 to a target position (machiningposition) (the X-axis direction: X3 of FIG. 8), and presses a set buttonwhich is provided on the control BOX 80. The movement to the X-axisdirection is performed by driving the motor. Further, the adjustmentother than the X-axis movement is the same as the operation methoddescribed using FIG. 8. When moving to the X-axis direction, the controlunit 103 acquires information on the target position (information on thenumber of pulses corresponding to the number of times of pressing thearrow button to move the slide milling holder 70 to the targetposition). The numerical value of the target position (for example,distance) may be set. In this case, for example, the set numerical value(distance) is converted into the number of pulses.

(iv) Step 1904

The control unit 103 acquires information on the target positionacquired in Step 1903 (a distance from the origin position: the numberof pulses generated when moving to the target position), and stores theinformation in a memory (not illustrated) in the control unit 103.

(v) Step 1905

When the setting of the target position is completed using the opticalmicroscope 40, the user takes the motor cable (out) 74 connected to theslide milling holder 70 out of the motor unit 72, and takes the slidemilling holder 70 out of the fixing base 42 of the optical microscope40. The control unit 103 detects that the motor cable (out) 74 is takenout.

(vi) Step 1906

Next, the user mounts the slide milling holder 70 taken out of theoptical microscope 40 on the rotating member 9 of the ion milling deviceinstalled in the vacuum chamber 15 (in the case of the ion millingdevice of FIG. 12) or on the sample unit base 5 (in the case of the ionmilling device of FIG. 1). Then, the user connects the motor cable (in)75 extending from the control unit 103 to the motor unit 72 of the slidemilling holder 70 through a vacuum chamber driver 104. The control unit103 detects that the motor unit 72 of the slide milling holder 70 isconnected to the motor cable (in) 75.

Then, the user closes the sample stage drawing mechanism 60, andevacuates the vacuum chamber 15 using the evacuation system 6 to make avacuum state.

(vii) Step 1907

The control unit 103 performs the initialization operation of the slidemilling holder 70. Specifically, a reference position (for example, theorigin point) of the slide milling holder 70 mounted in the ion millingdevice is moved.

The user injects argon gas between electrodes in the ion source 1, andapplies a high voltage thereto to start discharging. In this state, anacceleration voltage is applied, and the ion beam is emitted to startmachining.

(viii) Step 1908

The control unit 103 reads out the information on the target positionwhich is stored in the memory, controls the vacuum chamber driver 104such that the machining position on the sample is set to the targetposition, and drives the motor of the motor unit 72.

In the ion milling device, the rotating member 9 (in the case of theconfiguration example of the ion milling device of FIG. 10) or thesample stage 8 (in the case of the configuration example of the ionmilling device of FIG. 1) is tilted at an arbitrary angle in areciprocal manner, and performs a slide reciprocating drive of the slidemilling holder 70 (see FIG. 24) to obtain a wide machining surface (arange of the slide reciprocating drive is up to the position set belowthe optical microscope 40). Further, the slide reciprocating drive maybe performed continuously or intermittently. Further, as an example ofan intermittent drive, an operation of 0.1 mm of sliding after 10seconds machining→ . . . →0.1 mm of sliding after 10 seconds machiningmay be considered, and a holding (machining) time and a slide distancemay be input.

<Processing Content from Machining Target Position Setting to MachiningStart (Modification)>

FIG. 35 is a diagram illustrating a connection relation between deviceswhen the machining position of the ion milling device is set accordingto a modification. FIG. 36 is a flowchart for describing a procedure ofa machining position setting process according to the modification. Thedescription will be given with reference to FIGS. 35 and 36 about amethod of operating the ion milling (an operation from a state where thesample 3 is disposed on the sample mask unit 21) using the sample maskunit micromotion mechanism 4 on which the sample mask unit 21 installed.

In FIG. 18, the slide milling holder 70 having the motor unit 72 ismoved between the vacuum chamber 15 and the optical microscope 40 (usingthe same motor). However, in the modification, the drive unit (includingthe motor) is provided in each of the vacuum chamber 15 and the opticalmicroscope 40. Therefore, there is no need to move the slide millingholder 70 itself between the vacuum chamber 15 and the opticalmicroscope 40. Therefore, in this case, the sample mask unit micromotionmechanism. 4 on which the sample mask unit 21 installed may be movedback and forth between the vacuum chamber 15 and the optical microscope40, taking in and out the cable does not necessary at this time. In theprocedure of the machining position setting process illustrated in FIG.36, Steps 3601, 3602, and 3603 are performed instead of Steps 1901,1905, and 1906 of FIG. 19. Hereinafter, the description will be givenonly about Steps 3601 to 3603 which are different from FIG. 19.

(i) Step 3601

The user (operator) mounts the sample mask unit micromotion mechanism 4in the optical microscope 40 which includes the drive unit. To a motorunit 3502 on a side near the optical microscope 40, the motor cable(out) 74 which extends from the control unit 103 through the opticalmicroscope driver 102 is connected. Therefore, the connection procedureof the motor cable (out) is unnecessary unlike to Step 1901 of FIG. 19(only mounted to the optical microscope 40 of the sample mask unitmicromotion mechanism 4).

(ii) Step 3602

When the setting of the target position is completed using the opticalmicroscope 40, the user takes the sample mask unit micromotion mechanism4 out of the optical microscope 40 which includes the drive unit. Atthis time, the control unit 103 detects that the sample mask unitmicromotion mechanism 4 is taken out of the optical microscope 40, andcompletes the positioning in the optical microscope 40.

(vi) Step 3603

When the positioning in the optical microscope 40 is completed, the usermounts the sample mask unit micromotion mechanism 4 taken out of theoptical microscope 40 to the vacuum chamber 15 which includes the driveunit. To a motor unit 3501 on a side near the vacuum chamber 15 themotor cable (in) 75 extending from the control unit 103 through thevacuum chamber driver 104 is connected. Therefore, the connectionprocedure of the motor cable (in) is unnecessary unlike Step 1906 ofFIG. 19 (only mounted to the vacuum chamber 15 of the sample mask unitmicromotion mechanism 4). At this time, the control unit 103 detectsthat the sample mask unit micromotion mechanism 4 is mounted to thedrive unit of the vacuum chamber 15. Then, the user closes the samplestage drawing mechanism 60, and evacuates the vacuum chamber 15 usingthe evacuation system 6 to make a vacuum state.

<Specific Machining Region Setting Method at Wide Region Milling>

Herein, more specifically, the description will be given about a methodof setting a machining region in a case where the wide region milling isperformed. FIG. 20 is a diagram illustrating a layout example of buttonsfor setting the target position in the control BOX 80. FIGS. 21 and 22are diagrams illustrating a specific example of the machining regionsetting method of the wide region milling.

In a case where the wide region milling is performed, the user moves thesample 3 (the sample mask unit 21) using the control BOX 80 (or anoperation panel unit 80) (pressing an L button 76 (left) and an R button77 (right) in FIG. 20) while keeping an eye on (or timely looking at)the optical microscope 40, and sets both ends E1 and E2 of a region (amachining region 2101) which is machined as illustrated in FIG. 21(pressing a SET button 78 in FIG. 20).

In a method of setting a machining region of the wide region milling,the both ends of a region which is machined may be set as illustrated inFIG. 21. As illustrated in FIG. 22, a center Cl of the region which ismachined may be set (the machining region 2101). After setting, amachining region may be set by inputting numerical values (for example,a range of ±2 mm from the center) to the operation unit 81 (or thecontrol BOX 80) (in this case, a function of inputting numerical valuesto a machining region is added besides the buttons of FIG. 20) so as tomachine (slide reciprocating drive) the setting range (see FIG. 24). Themachining region of the wide region milling may be selected by any oneof the positions of both ends of the machining region and the centerposition of the machining region as illustrated in the operation screenof FIG. 23, so that operability is improved. The machining process(milling) is the same in any case where the machining region is setusing “the positions of both ends” and a case where the machining regionis set using “the center position”.

Further, as illustrated in FIG. 20, a multipoint milling select buttonand a wide region milling select button are provided in the control BOX80, and any one or both can be selected.

<Machining Procedure in Wide Region Milling>

FIG. 24 is a diagram for describing a machining procedure of the sample3 in the wide region milling.

When the wide region milling is performed, an emission absolute positionof an ion beam 2401 is fixed, and the sample 3 slides reciprocally in aslide range 2403 by the slide movement mechanism (the slide millingholder 70), and thus a wide machining surface 2402 is prepared (see FIG.24(a)).

Therefore, in a state where the ion beam 2401 is emitted, the slidemovement mechanism moves the sample 3 from the center to the right endof the machining surface 2402 (see FIG. 24(b)), and moves the samplefrom the right end to the left end of the machining surface 2402. Duringmoving the sample 3 from the right end to the left end of the machiningsurface 2402, the ion beam 2401 is emitted to the sample 3.

Subsequently, the slide movement mechanism slides the sample 3 from theleft end to the right end of the machining surface 2402 (see FIG.24(c)). During moving the sample 3 from the left end to the right end ofthe machining surface 2402, the ion beam 2401 is emitted to the sample3.

The above slide operation is repeatedly performed until the end of themachining (see FIGS. 24(d) and 24(c)).

<Reason Why Slide Movement Mechanism is Provided on Rotating Member>

According to the configuration of the device described above, the slidemovement mechanisms (the slide milling holder 70) is provided on therotating member 9 (the sample stage 8 in a case where the configurationof the ion milling device of FIG. 1 is employed). In other words, themachining position on the reciprocating slope axis and the upper surfaceof the sample is always the same. Therefore, even when the sample 3 isdriven to slide while reciprocating and tilting, interference hardlyoccurs in the mechanism units (the ion source 1, the ion beam probe,etc.) in the sample chamber. Accordingly, the limitation of the sliderange is also less.

FIG. 25 is a diagram illustrating a range of a reciprocating slopeoperation of the sample in the case of a normal cross-sectional milling(a configuration where the slide movement mechanism is not provided).FIG. 26 is a diagram illustrating a range of the slide operation and thereciprocating slope operation in a case where the slide movementmechanism (the slide milling holder 70) is installed below the rotatingmember 9. FIG. 27 is a diagram illustrating a range of the slideoperation and the reciprocating slope operation in a case where theslide movement mechanism (the slide milling holder 70) is installed onthe rotating member 9.

In the case of the normal cross-sectional milling (FIG. 25), the samplemask unit 21 does not slide to move, and thus the position of a rotationtilting shaft (a rotation shaft of the rotating member 9) 2502 is fixed,and a reciprocating slope operation 2503 is performed within the fixedrange. Therefore, the sample mask unit 21 performing the reciprocatingslope operation 2503 does not receive interference from an ion beamprobe 2501 and the ion source 1.

On the other hand, as illustrated in FIG. 26, in a case where the slidemovement mechanism (the slide milling holder 70) is installed below therotating member 9, the position of the rotation tilting shaft 2502 alsoslide when the sample mask unit 21 slides. In addition, the sample maskunit 21 performs the reciprocating slope operation 2503 while therotation tilting shaft 2502 slides (a slide direction 2601 is constant).Therefore, the sample mask unit 21 interferes with the ion beam probe2501 and the ion source 1 depending on the position of the rotationtilting shaft 2502 (interference place 2602), and a sufficiently widemachining width may not be obtained.

Therefore, as illustrated in FIG. 27, the slide movement mechanism (theslide milling holder 70) is installed on the rotating member 9. In thiscase, the position of the rotation tilting shaft 2502 is fixed even whenthe sample mask unit 21 slides. Therefore, a slide direction 2701changes depending on the tilting angle of the reciprocating slopeoperation 2503, but the sample mask unit 21 does not cause interferencewith the ion beam probe 2501 and the ion source 1 during the slideoperation and the reciprocating slope operation. Therefore, a wide slidewidth can be obtained at the time of sliding, and a wide machining widthcan be obtained. Further, if the multipoint milling is performed in theconfiguration of FIG. 26, the position of the rotation tilting shaft2502 changes as described above in a case where a position separatedfrom the ion beam axis is machined. Therefore, there is a problem inthat a milling profile is not normally formed (the milling profile isformed asymmetrically in the horizontal direction).

<Specific Method of Setting Machining Place in Multipoint Milling>

Herein, more specifically, the description will be given about a methodof setting a machining place in a case where the multipoint milling isperformed. FIG. 28 is a diagram illustrating a specific example of themachining region setting method of the multipoint milling.

Even in a case where the multipoint milling (automatic machining on aplurality of places) is performed, the sample 3 (the sample mask unit21) is moved in the control BOX 80, or the operation unit 81 (press theL button 76 (left) and the R button (right)) while keeping eye on theoptical microscope 40 (or timely looking at) similarly to the case ofthe wide region milling. More specifically, as illustrated in FIG. 28(in the case of two or more machining places), a plurality of positionsP1 and P2 to be machined are set (press the SET button 78). Further,even in a case where the multipoint milling is performed, the mask 2 isdesirably fixed to make the edge thereof arranged in parallel to asliding direction.

After setting the machining position, the motor cable (out) 74 is takenout of the slide milling holder 70, and the slide milling holder 70 istaken out of the fixing base 42. Then, the slide milling holder 70 ismounted in the rotating member 9 or the sample unit base 5, and themotor cable (in) 75 is connected to the slide milling holder 70.

The sample stage drawing mechanism 60 is closed, and the vacuum chamber15 is evacuated by the evacuation system 6 to be a vacuum state. Inaddition, an argon gas is injected between the electrodes in the ionsource 1, a high voltage is applied, and the discharging is started. Inthat state, the acceleration voltage is applied, the ion beam isemitted, and the machining starts (at the same time, the reciprocatingslope operation is performed).

<Procedure of Machining by Multipoint Milling>

FIG. 29 is a diagram for describing a first machining procedure of thesample 3 by the multipoint milling. FIG. 30 is a diagram for describinga second machining procedure to suppress the redeposition by themultipoint milling.

As illustrated in FIG. 29 (in the case of two machining places), whenthe machining is completed at a first machining position 2901 (amachining surface 2902), the slide milling holder 70 is automaticallydriven to slide (in X3 direction) and moves to a second machiningposition 2904 (a slide driving direction 2903), and the machiningstarts. In a case where a third machining position and the subsequentpositions are selected, the above process is performed. With the abovemachining method, the multipoint milling (automatic machining on aplurality of places) can be realized.

However, in a case where the machining is performed with the method, aredeposition 3003 may be generated in the surface of a first machiningsurface 3001 as illustrated in FIG. 30 (a). As a countermeasure, forexample, in a case where each of the machining positions is set to bemachined for 3 hours, the machining is performed as follows: one hourmachining at the first machining position 2901 (the first machiningsurface 3001) (first) moving to the second machining position 2904 (asecond machining surface 3002), one hour machining (first) again, movingto the first machining position 2901 (the first machining surface 3001),one hour machining (second) moving to the second machining position 2904(the second machining surface 3002), one hour machining (second) again,moving to the first machining position 2901 (the first machining surface3001), one hour machining (third) moving to the second machiningposition 2904 (the second machining surface 3002), and one hourmachining (third). Then, the machining process is ended (the case ofFIG. 30(b)). Further, the same process is also applied to the cases ofFIGS. 30(c) and 30(d). In the case of the above machining method, thefirst machining hour is short, and thus the redeposition amount of themachining surface is significantly reduced. In addition, theredeposition generated in the machining surface is removed in the nextmachining, so that a good cross section is obtained. In the setting ofthe machining method, the machining time period of one place is dividedinto several periods, or dividing hours may be input.

In addition, a machining method illustrated in FIG. 30(e) may beemployed. In other words, for example, about 95% machining is completedat the first machining position 2901 (the first machining surface 3001)(first), the process moves to the second machining position 2904 (thesecond machining surface 3002) to complete the machining at the secondmachining position 2904 (the second machining surface 3002) by onemachining (for example, 3 hours of machining). Then, the process movesto the first machining position 2901 (the first machining surface 3001)again, and the machining at the first machining position 2901 (the firstmachining surface 3001) is completed. With this configuration, themachining hour in the first machining position 2901 (the first machiningsurface 3001) can be set to be significantly short. Therefore, it ispossible to significantly prevent the redeposition 3003 from beinggenerated in the second machining position 2904 (the second machiningsurface 3002).

Further, a machining method as illustrated in FIG. 30(f) may beemployed. In other words, the machining at the first machining position2901 (the first machining surface 3001) is completed by one time (forexample, 3 hours of machining), the process moves to the secondmachining position 2904 (the second machining surface 3002), and iscompleted by one time of machining (for example, 3 hours of machining).Then, the process moves to the first machining position 2901 (the firstmachining surface 3001) again, and a finishing process is performed atthe first machining position 2901 (the first machining surface 3001) byan acceleration voltage which is weaker than that at the time ofmachining. Further, the process moves to the second machining position2904 (the second machining surface 3002) again, and the finishingprocess is performed similarly. With such a finishing process performedlast, the redeposition can be removed even the redeposition is generatedat a machining position, and a desired machining can be realized.

Further, when the multipoint milling is performed as described above (inthe case of FIGS. 30(b) to 30(f)), the respective machining positionsare set, and the number of times of machining and the machining hours ateach machining place are set.

To sum up the multipoint milling described above, a plurality ofmachining positions and the number of milling operations in each of theplurality of machining positions are set, and the sample is machined ateach machining position according to the information on each machiningposition and the number of milling operations at each machiningposition. At that time, at least one milling operation is performedalternately in at least one of the plurality of machining positions. Inother words, for example, one time of milling operation is necessarilyperformed at each machining position in an alternate manner asillustrated in FIGS. 30(b) to 30(f). In addition, a plurality of timesof milling operations are performed in at least one of the plurality ofmachining positions with a time interval therebetween. In other words,for example, in FIG. 30(b), after a first milling operation is performedat a first machining surface 3001, the first milling operation isperformed at a second machining position 3002 before a second millingoperation is performed. In addition, the final machining is performedsequentially at the respective machining positions (see FIGS. 30(b) to30(d), and 30(f)).

In the ion milling device of the related art, when the machining iscompleted at one place, there is a need to evacuate the vacuum chamberto the air once, change the machining position, and make the vacuumchamber be the vacuum state again. With this regard, in the ion millingdevice according to the embodiment, the machining is automaticallyperformed on a plurality of places (for example, 3 places), so that themachining can be performed on the plurality of places at one time.Therefore, it is possible to easily obtain an optimal machiningcondition of the machining sample. More specifically, the multipointmilling can set the respective machining conditions (discharge voltage,acceleration voltage, current amount, reciprocating slope angle, coolingtemperature, etc.) at the respective machining positions. Therefore, itbecomes easy to approach an optimal condition. For example, a sample ismachined under a condition that the acceleration voltage at the firstplace is set to 2 kV, the acceleration voltage at the second place isset to 4 kV, and the acceleration voltage at the third place is set to 6kV.

In addition, it is possible to employ many applications by setting thewide region milling at the respective machining positions of themultipoint milling.

<Applications of Wide Region Milling>

FIG. 31 is a diagram illustrating an application of the wide regionmilling. Herein, the description will be given about a case where amachining place is not set clearly. This machining method is effectivein a case where the machining is performed in a short time.

According to the related art, as illustrated in FIG. 31(a), in a casewhere the position of a machining object (for example, defect) isunclear, a machining surface 3102 is necessarily machined by an ion beam3101 at an approximate position. However, there is a possibility to taketoo much time in such a method.

Therefore, a machining object is found and machined with efficiency byusing the wide region milling. Specifically, as illustrated in FIG.31(b), the wide region milling is performed (emitting a beam whilereciprocating, tilting, and driving the sample 3 to slide). When amachining object (position) 3103 is found (an optical microscope formachining observation (installed in the upper portion of the machiningobservation window 7), or naked eye), the machining is stopped. Next, asillustrated in FIG. 31(c), the sample holder is moved (slid) to matchthe ion beam axis to the machining position, and a normal milling isperformed.

The method in which the wide region milling applied to find a machiningposition and a normal milling having a high milling rate are combinedcan significantly shorten the machining hours compared to a case wherethe wide region milling is performed to the end.

<Application of Multipoint Milling>

FIGS. 32 to 34 are diagrams for describing an application of themultipoint milling. FIG. 32 is a diagram for describing a method offixing a plurality of samples having different thicknesses. FIG. 33 is adiagram illustrating a state where the plurality of samples havingdifferent thicknesses are arranged and fixed to a mask. FIG. 34 is adiagram illustrating a state where the samples having differentthicknesses are machined and moved to an observation device forobservation.

Herein, the description will be given about a method of performing onetime of the cross-sectional milling on a plurality of samples as anapplication of the multipoint milling. In a normal cross-sectionalmilling, the sample holder 23 bonded with the sample 3 is installed inthe sample mask unit 21. In the sample fixing method, in a case wherethe sample having a different thickness is bonded to the sample holder23, a gap occurs between the sample (thin one) and the mask 2 when thesample having a different thickness is disposed, and thus a smooth crosssection is not obtained.

Therefore, the sample is fixed using a projection adjusting tool 90 asillustrated in FIGS. 32(a) to 32(c). First, the upper surface (near aportion where the ion beam emits) of the mask 2 comes into contact witha base 91 of the projection adjusting tool 90, and the mask 2 is fixedby a fixing screw 92. When the mask 2 is fixed, a contact surfacebetween the mask 2 and a position adjusting base 93 is made in parallelusing the right wall of the base 91. A gap 3201 between the mask 2 andthe position adjusting base 93 (moving along the linear guide) isadjusted using a micrometer 94. When the gap 3201 is large, themicrometer 94 is turned in a counterclockwise direction and pressed by apressure of a spring 95. After fixing the mask 2 to the base 91, themicrometer 94 is turned to bring the position adjusting base 93 intocontact with the mask 2. A value (initial value) of the micrometer atthat time is stored.

Next, the micrometer 94 is turned in a counterclockwise direction toadjust the gap 3201 between the mask 2 and the position adjusting base93. A distance (which is equal to a projection amount to be describedbelow) of the gap 3201 becomes a value from which the current value andthe initial value of the micrometer 94 are subtracted. Therefore, thedistance may be adjusted to any value. After setting the distance of thegap 3201, the fixing position is determined while bringing the sample 3into contact with the position adjusting base as illustrated in FIG.32(c), and the sample 3 is brought into direct contact with the mask 2(the surface of the sample 3 where the ion beam is emitted is broughtinto contact with the mask 2). When the sample is bonded as describedabove, the distance of the gap 3201 becomes equal to a projection amount3301. Further, since the sample 3 can be directly fixed to the mask, itis possible to arrange and fix the plurality of samples having differentthicknesses. While not illustrated in the drawings, the projectionamount 3301 of the sample 3 may be different from each other (see FIG.33).

After fixing (bonding) all the samples to the mask 2, the fixing screwis released to take the mask 2 to which the sample is fixed out of theprojection adjusting tool. The mask 2 is fixed to the mask holder 25(the sample mask unit 21) using the mask fixing screw 27. With thefixing method and the multipoint milling (description of theabove-described adjustment of X and Y (X3 and Y3 of FIG. 8 (herein, X3corresponds to a motor driving) of the sample mask unit micromotionmechanism 4 will be omitted)), the plurality of samples can be machinedby one time of the milling process.

After the plurality of samples fixed to the mask 2 is machined, the mask2 is taken out of the ion milling device, and attached to a sampledisposing base 105 of an observation device (SEM) (see FIG. 34). Thesample disposing base 105 is configured to fix the mask 2 to a fixingscrew 106, and the mask 2 fixed to the sample 3 can be easily fixed tothe sample disposing base 105.

In addition, a female screw (in a case where a male screw 3402 isprovided near a sample fixing base 107 of the observation device) 3401is provided in the bottom surface of the sample disposing base 105, andmay be fixed to the male screw 3402 of the sample fixing base 107 of theobservation device. Therefore, the mask 2 fixed with the sample 3 iseasily disposed in the observation device, and can be observed. Theposition of the female screw 3401 of the sample disposing base 105 isdesirably set such that the machining surface is disposed on the centeraxis of the male screw 3402 so as to easily find the machining surfaceat the time of observation.

<Modifications>

(i) In the ion milling device illustrated in FIGS. 1 and 10, the samplemask unit micromotion mechanism 4 on which the sample mask unit 21 ismounted is detachably connected to the sample unit base 5.

However, even in a case where the sample unit base 5 and the sample maskunit micromotion mechanism 4 to which the sample mask unit 21 is mountedare formed integrally, the same machining is possible by mounting theoptical microscope 40 in the device. Further, in this case, the motorcable (out) 74, the motor cable (in) 75, and the slide milling holder 70are not possible to be taken in and out, but a space for adjusting thepositions may be limited.

(ii) In the embodiment, the description has been given on an assumptionthat the ion milling device and the observation device (SEM) areconfigured separately. However, these devices may be integrallyconfigured. In this case, for example, there is provided a mechanismwhich shares the sample unit base 5 and the sample mask unit 21, andswitches the ion source used at the time of the ion milling and anelectronic gun used at the time of observing the machining surface.Since the information on a machining place of the ion milling (positioninformation) is stored in the control unit 103, the information may beused even in the observation device, and there are advantages that thecontrols such as positioning at the time of observation are easilyperformed. In addition, the sample after machining is taken out of theion milling device. Further, a labor for installing the observationdevice may be saved, so that the throughput from the machining to theobservation may be improved.

<Conclusions>

(i) In the wide region milling, the reciprocating slope operation andthe slide operation are performed at the same time during emitting theion beam, so that a wide machining width is obtained regardless of thediameter of the ion beam. Therefore, it is effective to a sample whichis necessary for a wide range of observation and analysis. In addition,after finishing the cross-sectional milling (the reciprocating slopeoperation during emitting the ion beam), the multipoint milling isperformed to slide the sample to a predetermined machining position (orpositions), and the cross-sectional milling may be further performed onthe position. Therefore, the machining is automatically performed at aplurality of positions, and it is possible to improve the throughput.

The ion milling device according to the embodiment includes a samplesliding mechanism which slides the sample holder in a directionincluding a normal direction of the axis of the ion beam. In addition,the ion milling device may include a rotation mechanism which rotatesand tilts the sample holder by turning an axis perpendicular to thesliding direction of the sample sliding mechanism. In this case, theslide movement mechanism (motor drive) is desirably disposed in theupper portion of the rotation mechanism (a mechanism of which thereciprocating slope (rotation) axis does not move even in a case wherethe slide operation is performed), and a position of the rotation shaftof the rotation mechanism does not desirably moved. In addition, therotation shaft of the rotation mechanism is preferably positioned on apath of the ion beam. Further, the slide movement mechanism desirablyslides the sample in a surface perpendicular to the rotation shaft ofthe rotation mechanism. With this configuration, while emitting the ionbeam, the sample is subjected to the reciprocating slope operation (anormal cross-sectional milling), and also the reciprocating slideoperation (a slide operation wider than the ion beam width) isperformed. With this machining method, a desired machining width isobtained by one time of processing (wide region milling). The machiningwidth of the wide region milling is not limited to the ion beam width,so that it is possible to obtain a wide range of the machining surface(observation surface).

In addition, after completing the cross-sectional milling using theslide movement mechanism, the machining is automatically moved (slid) tothe next machining position, and the cross-sectional milling isperformed at the moved position again. With this machining method, it ispossible to automatically perform the cross-sectional milling on aplurality of places (multipoint milling). Since the cross-sectionalmilling of the plurality of places can be performed by one time ofprocessing, the multipoint milling can improve the throughput.

(ii) The ion milling device according to the embodiment includes the ionsource which emits the ion beam, the sample holder which holds thesample, the sample sliding mechanism which slides the sample holder in adirection including a normal direction of the axis of the ion beam, anda control unit. The control unit controls the sample sliding mechanismbased on machining information which is input regarding a machiningcontent of the sample, and allows the wide region milling which isperformed on the sample over a range wider than the width of the ionbeam, and/or the multipoint milling which is performed on a plurality ofplaces of the sample to be performed. With this configuration, it ispossible to automatically perform the wide region milling and themultipoint milling by one ion milling device. In addition, it is alsopossible to combine the wide region milling and the multipoint milling.

(iii) The ion milling device according to the embodiment includes a userinterface unit which is possible to select at least one of the wideregion milling which is performed on the sample over a region wider thanthe width of the ion beam and the multipoint milling which is performedon a plurality of places of the sample, and the control unit whichcontrols the milling operation with respect to the sample based on aselection input with respect to the user interface unit. With thisconfiguration, the user is able to perform a desired milling operationwith efficiency by selecting one of the wide region milling and themultipoint milling, or by combining two milling operations.

Further, in a case where the wide region milling and the multipointmilling both are selected, the control unit controls the millingoperation while switching the operation between the wide region millingand the multipoint milling. With this configuration, it is possible toperform the wide region milling and the multipoint milling withefficiency by one time of processing.

(iv) In the embodiment, when the ion milling is performed, first, thesample is disposed on the optical microscope. Then, the opticalmicroscope is used to set the machining position and the machining widthof the wide region milling which is performed on the sample over aregion wider than the width of the ion beam, and the plurality of themachining positions of the multipoint milling which is performed on theplurality of places of the sample with respect to the sample. Next, theinformation on the machining position and the machining width of thewide region milling, and the information on the plurality of machiningpositions of the multipoint milling are transmitted to the control unitwhich controls the milling operation. Then, the sample is taken out ofthe optical microscope, and disposed in the ion milling device. Thecontrol unit controls the milling operation in the ion milling devicebased on the information on the machining position and the machiningwidth of the wide region milling and the information on the plurality ofmachining positions of the multipoint milling. With the aboveoperations, the wide region milling and the multipoint milling areperformed. With this configuration, it is possible to automaticallyperform the wide region milling and the multipoint milling withefficiency by one time of processing. Further, the same procedure isperformed even in a case where only one of the wide region milling andthe multipoint milling is performed.

(v) The multipoint milling may be performed along the followingprocedure. First, the plurality of machining positions when themultipoint milling is performed and the number of milling operations atthe plurality of machining positions are set. Next, the plurality ofmachining positions of the sample are machined according to theinformation on the plurality of machining positions and the number ofmilling operations. At that time, at least one milling operation in atleast a part of the plurality of machining positions is performedalternately, and a plurality of times of milling operations areperformed on at least one of the plurality of machining positions with atime interval therebetween. In a case where the milling operation isperformed with a time interval, the milling operation at the othermachining position is performed during the time interval. With thisconfiguration, it is possible to significantly reduce the redepositionwhich is likely to be generated in the respective machining positions.

In addition, the final stage of machining (the final milling operation)may be sequentially performed on the plurality of machining positions.In this way, the final machining is sequentially performed at therespective machining positions, so that it is possible to significantlysuppress the redeposition which is likely to be generated at therespective machining positions.

Further, the finishing machining may be performed at an accelerationvoltage weaker than that used when the machining is performedalternately at the plurality of machining positions. Even in this case,the same effect of suppressing the redeposition can be achieved.

(vi) According to the embodiment, it is possible to perform thefollowing milling. First, the wide region milling is performed on thesample over a region wider than the width of the ion beam, and themachined places are searched. Then, the machined place where thedeposition is found is subjected to the wide region milling in a depthdirection of the sample. With this configuration, the hardly foundplaces can be found by the wide region milling with efficiency, and thenthe places can be subjected to an intense milling. Therefore, it ispossible to improve the throughput.

(vii) According to the embodiment, the milling may be performed alongthe following procedure. First, the plurality of samples are attached tothe sample mask such that the sample protrudes from the mask by apredetermined amount. Next, the machining position is set with respectto each of the plurality of samples. Then, the ion beam is emitted tothe sample from the sample mask, the multipoint milling is performed tomachine a plurality of places of the sample, and the plurality ofsamples are machined. In this case, the plurality of samples may includesamples having different thicknesses. With this configuration, thesamples having different thicknesses can be subjected to the milling byone time of processing. In addition, it is possible to avoid a risk suchas a gap generated between the sample and the mask due to the differentthickness of the sample, and the redeposition generated due to the ionbeam going around the gap.

REFERENCE SIGNS LIST

-   -   1: ion source    -   2: mask    -   3: sample    -   4: sample mask unit micromotion mechanism    -   5: sample unit base    -   6: evacuation system    -   7: machining observation window    -   8: sample stage    -   9: rotating member    -   10: flange    -   11, 24: linear guide    -   12: loupe    -   13: loupe micromotion mechanism    -   15: vacuum chamber    -   21: sample mask unit    -   22: sample holder rotation ring    -   23: sample holder    -   25: mask holder    -   26: mask fine adjustment mechanism    -   27: mask fixing screw    -   28: sample holder rotation screw    -   29: reverse rotating spring    -   30: sample holder position control mechanism    -   35: sample holder metal fitting    -   40: optical microscope    -   41: observation stand    -   42: fixing base    -   50: gear    -   51: bearing    -   52: mask unit fixing unit    -   53: shaft coupling    -   54: linear device    -   55: motor    -   60: sample stage drawing mechanism    -   70: slide milling holder    -   71: X gear    -   72: motor unit    -   73: M gear    -   74: motor cable (out)    -   75: motor cable (in)    -   76: L button    -   77: R button    -   78: SET button    -   80: control BOX    -   81: operation unit    -   90: projection adjusting tool    -   91: base    -   92: fixing screw    -   93: position adjusting base    -   94: micro meter    -   95: spring    -   100: ion milling device    -   101: shutter    -   102: optical microscope driver    -   103: control unit    -   104: vacuum chamber driver    -   105: sample disposing base    -   106: fixing screw    -   107: sample fixing base    -   2101: machining region    -   2401: ion beam    -   2402: machining surface    -   2403: slide range    -   2501: ion beam probe    -   2502: rotation tilting shaft    -   2503: reciprocating slope operation    -   2601: slide direction    -   2602: interference place    -   2701: slide direction    -   2901: first machining position    -   2902: machining surface    -   2903: slide driving direction    -   2904: second machining position    -   3001: first machining surface 3001    -   3002: second machining position    -   3003: redeposition    -   3101: ion beam    -   3102: machining surface    -   3103: machining object    -   3201: gap    -   3301: projection amount    -   3401: female screw    -   3402: male screw    -   3501: motor unit    -   3502: motor unit

1. An ion milling device which emits an ion beam to a sample to machinethe sample, comprising: an ion source which emits the ion beam; a sampleholder which holds the sample of which at least a part is shielded by amask; a sample sliding mechanism which slides the sample holder in adirection including a normal direction of an axis of the ion beam; and arotation mechanism which rotates and tilts the sample holder around anaxis perpendicular to a direction of a sliding movement caused by thesample sliding mechanism.
 2. The ion milling device according to claim1, wherein the sample sliding mechanism slides the sample with a widthwider than a width of the ion beam.
 3. The ion milling device accordingto claim 1, wherein the sample sliding mechanism is installed above therotation mechanism, and a position of a rotation shaft of the rotationmechanism is constant.
 4. The ion milling device according to claim 3,wherein the rotation shaft of the rotation mechanism is on a path of theion beam.
 5. The ion milling device according to claim 4, wherein theslide movement mechanism slides the sample in a plane perpendicular tothe rotation shaft of the rotation mechanism.
 6. The ion milling deviceaccording to claim 1, further comprising: a user interface unit which isused to set a machining position and a machining width in a wide regionmilling which machines the sample in a range wider than a width of theion beam; and a control unit which controls a movement of the samplesliding mechanism based on the machining position and the machiningwidth which are set by the user interface unit.
 7. The ion millingdevice according to claim 1, further comprising: a user interface unitwhich is used to set a machining position in a multipoint milling whichmachines a plurality of places of the sample; and a control unit whichcontrols a movement of the sample sliding mechanism based on informationon the machining position which is set by the user interface unit.
 8. Anion milling device which machines a sample by emitting an ion beam tothe sample of which at least a part is shielded by a mask, comprising:an ion source which emits the ion beam; a sample holder which holds thesample; a sample sliding mechanism which slides the sample holder in adirection including a normal direction of an axis of the ion beam; and acontrol unit, wherein the control unit controls the sample slidingmechanism based on machining information which is input regarding amachining content of the sample, and allows a wide region milling whichmachines the sample in a range wider than a width of the ion beam and/ora multipoint milling which machines a plurality of places of the sampleto be performed.
 9. An ion milling device which machines a sample byemitting an ion beam to the sample of which at least a part is shieldedby a mask, comprising: a user interface unit which is capable ofselecting at least one of a wide region milling which machines thesample in a region wider than a width of the ion beam and a multipointmilling which machines a plurality of places of the sample; and acontrol unit which controls a milling operation on the sample based on aselection input on the user interface unit.
 10. The ion milling deviceaccording to claim 9, wherein in a case where the wide region millingand the multipoint milling both are selected by the user interface unit,the control unit controls the milling operation while switching anoperation between the wide region milling and the multipoint milling.11. An ion milling method which machines a sample by emitting an ionbeam to the sample of which at least a part is shielded by a mask,comprising: disposing the sample on an optical microscope, and setting amachining position and a machining width of a wide region milling whichmachines the sample in a region wider than a width of the ion beam and aplurality of machining positions of a multipoint milling which machinesa plurality of places of the sample using the optical microscope;transmitting information on the machining position and the machiningwidth of the wide region milling, and information on the plurality ofmachining positions of the multipoint milling to a control unit whichcontrols a milling operation; taking the sample out of the opticalmicroscope and disposing the sample on an ion milling device; andcausing the control unit to control the milling operation in the ionmilling device based on the information on the machining position andthe machining width of the wide region milling and the information onthe plurality of machining positions of the multipoint milling.
 12. Anion milling method which machines a sample by emitting an ion beam tothe sample of which at least a part is shielded by a mask, comprising:disposing the sample on an optical microscope, and setting a machiningposition and a machining width of a wide region milling which machinesthe sample in a region wider than a width of the ion beam using theoptical microscope; transmitting information on the machining positionand the machining width of the wide region milling to a control unitwhich controls a milling operation; taking the sample out of the opticalmicroscope and disposing the sample on an ion milling device; andcausing the control unit to control the milling operation in the ionmilling device based on the information on the machining position andthe machining width of the wide region milling.
 13. An ion millingmethod which machines a sample by emitting an ion beam to the sample ofwhich at least a part is shielded by a mask, comprising: disposing thesample on an optical microscope, and setting a plurality of machiningpositions, in the sample, of a multipoint milling which machines aplurality of places of the sample using the optical microscope;transmitting information on the plurality of machining positions of themultipoint milling to a control unit which controls a milling operation;taking the sample out of the optical microscope and disposing the sampleon an ion milling device; and causing the control unit to control themilling operation in the ion milling device based on the information onthe plurality of machining positions of the multipoint milling.
 14. Anion milling method which uses an ion milling device to machine a sampleby emitting an ion beam to the sample of which at least a part isshielded by a mask, comprising: setting a plurality of machiningpositions when a multipoint milling which machines a plurality of placesof the sample is performed; setting the number of times of millingoperations in the plurality of machining positions; and machining theplurality of machining positions of the sample according to informationon the plurality of machining positions and the number of times ofmilling operations, wherein when the plurality of machining positionsare machined by the multipoint milling, at least one time of millingoperation is alternately performed in at least a part of the pluralityof machining positions, and a plurality of times of milling operationsis performed in at least one machining position of the plurality ofmachining positions with a time interval therebetween.
 15. The ionmilling method according to claim 14, wherein the milling operation isperformed in another machining position between the milling operationsin the at least one machining position where the plurality of millingoperations are performed with a time interval therebetween.
 16. The ionmilling method according to claim 14, wherein a final stage of machiningis sequentially performed in the plurality of machining positions. 17.The ion milling method according to claim 14, further comprising:performing a finishing machining with an acceleration voltage weakerthan an acceleration voltage used when the machining is performedalternately in the plurality of machining positions.
 18. An ion millingmethod which uses an ion milling device to machine a sample by emittingan ion beam to the sample of which at least a part is shielded by amask, comprising: performing a wide region milling on the sample in aregion wider than a width of the ion beam, and searching a machiningplace; and performing milling, in a depth direction of the sample, onthe machining place found out by the wide region milling.
 19. An ionmilling method which uses an ion milling device to machine a sample byemitting an ion beam to the sample of which at least a part is shieldedby a mask, comprising: attaching a plurality of samples to a sample maskto protrude from the sample mask by a predetermined amount; settingmachining positions in the plurality of samples; and emitting the ionbeam from the sample mask to the sample, performing a multipoint millingwhich machines a plurality of places of the sample, and machining eachof the plurality of samples.
 20. The ion milling method according toclaim 19, wherein the plurality of samples include a sample havingdifferent thickness.